If you were going to design the most fattening job possible, say Richard Stuart and Barbara Jacobson, it would include these elements: a good deal of cooking, long hours, minimal contact with adults, loneliness and the necessity of performing tasks so mundane that munching would be fascinating by comparison. In addition, this job would be both a low-status and volunteer position, making the employe financially and emotionally dependent on someone else.

Sound familiar? It's the life of a full-time homemaker. No wonder that, in Stuart and Jacobson's survey of nearly 25,000 weight-conscious women (41.7 percent of whom were employed nine hours a week or less), 90 percent failed to achieve their diet goals.

Apparently, both the working and home-bound dieters were doing the wrong thing. Concentrating on reducing food intake only obscured the conditions that caused both over-eating and being overweight in the first place.

"We've found there are a great many women who say they want to be thin but really do need to be fat. Probably 75 percent of the women in America who believe they have weight problems have mislabeled their situation," says Stuart, 53. A former psychological director of Weight Watchers International, he'll start next month as a clinical professor of psychiatry at the University of Washington.

Says Jacobson: "It's a weight problem, but not a food problem." A former student of Stuart's and now his wife, she is currently finishing her doctorate in counseling psychology at the University of Utah. Together, they've written Weight, Sex and Marriage: A Delicate Balance (Norton, $15.95), which analyzes the survey results.

Jacobson, 35, also has some personal experience with the subject.

"This is what I wish someone had told me when I had a weight problem: 'In your life, overeating makes sense,' " she says. "What so many women feel is, 'I have no control. I know I should be losing weight, but the brownies cry out at me.' It's as if there is a mysterious power that drives us to overeat. The problem is, as long as it's not understandable, it's not changeable."

The key to understanding women's weight loss, according to Stuart and Jacobson, is realizing that overeating has a purpose. Diets often don't work because they take this approach backward: eat less and your problems will disappear. Instead, they argue, you should find out the gap that food is emotionally designed to fill -- loneliness, boredom, anger at your husband -- and discover a way to get it met besides stuffing yourself. Slimness will then come on its own.

To be sure, just plain dieting seems easier. "It's more socially acceptable to be working on your weight than talking about marital or self-esteem problems," says Jacobson. "No woman is embarrassed with a diet, whereas she's probably not going to say to her best friend, 'My husband's not affectionate enough.' "

Getting hitched is like receiving your college diploma: you've passed all the tests and taken the prize, so why bother to keep up your studies?

"Before I got married, crash diets were as much a part of my life as work and sleep," a woman wrote on her questionnaire. " ... Looking my best was my top priority, and I didn't mind doing what it took to look good in tight jeans or a slinky evening dress.

"But once I settled into married life, I lost all my willpower. I think it was because I knew my husband loved me and would stay with me no matter how I looked ... But since I've decided to let myself go, I've gone up three dress sizes."

With other spouses, the reasons for weight gain are more complex. "You talk to a couple, he'll say, 'First she got fat, then our sex life disappeared,' " says Stuart. "The wife is more likely to say, 'He stopped paying attention shortly after we got married. It's not like when he was courting. So out of my loneliness and frustration, I turned to food.' "

In any case, it's important to separate reasons for overeating from reasons for being overweight. Overeating tends to provide emotional or sensual rewards. It cures boredom, loneliness, anxiety or stress. In more ways than one, it will fill a void.

Yet while all overweight women mismanage their food intake, some -- Stuart estimates 40 percent -- also benefit from being fat. Reasons for this include protection from the following:

The threat of extramarital sex. "I know it sounds dumb, but I think one of the reasons I overeat is to be sure I'm not attractive to other men," wrote one woman in the survey. "When I am near my low weight, I get a lot of male attention, and I love it. ... Then I feel guilty about my flirtations, and I start eating again."

Her own impulse for sexuality. Women who feel uncomfortable receiving sexual attention may gain weight to lessen that chance. "Lately, I find late night snacks much more enjoyable than sex," said another survey respondent. "And if an extra 10 pounds makes him less interested, so much the better."

The risk of failure. "When I'm fat, people expect so little of me that there's no way I can disappoint them," a third woman said. " ... I don't know if people would be as impressed if I were thin ... It would be devastating to discover I'm only impressive 'for a fat lady.' "

Hostility. "From the day we were engaged, he was after me about what I ate. He was terrified about having a fat wife ... ," wrote a woman who weighed only 112 pounds when she tied the knot. "It made me so mad ... and it still does ... So I finally figured if I can't eat while he's here, I'll eat when he's not around."

Behind every fat wife, there is a husband. Whether he's chubby or a stick, what's his role in all this?

Stuart and Jacobson were able to isolate in their survey a group of women who were 60 pounds or more above their ideal weight, and a group within 15 pounds of their ideal weight. Among those successful at weighing close to their ideal, about half attributed their achievement to the fact that their husbands were so respectful they allowed them to keep their weight their own business. The other half said their husbands were so helpful they did everything up to and including dieting with them.

Of the unsuccessful women, half attributed their failure to the fact that the husbands were so uninterested they never paid any attention to the wife's weight at all. The other half felt the opposite: Their husbands were so disrespectful of their ability to shed excess baggage they insisted on being involved. "He would presume to ask me if I really wanted to eat that cake," said one woman. "That infuriated me, so I ate it."

Stuart's conclusion: "There's not one right way. Each woman has her own definition of help and hindrance. It's her responsibility to tell her husband what she'd like him to do, and also reassure him that if she loses weight, he won't lose her."

According to the survey, however, that's precisely what a small number of women intend to do. When they were asked their commitment to stay married, 1.9 percent said they were definitely planning to leave, while 6.4 percent said they might -- and many of these women were presumably still overweight, and weren't experiencing the thrills and temptations of being trim.

Even if she's not intending to flee, losing weight can upset the balance of power in the relationship -- another reason for the husband to be truculent. "If she's very overweight," says Jacobson, "typically she may have no self-confidence, and let him run the show. Or he might feel totally justified in being an alcoholic, a workaholic or having his own weight problems. He can use {her heaviness} to justify things that she would never tolerate if she was feeling better about herself."

A man who marries an overweight woman, the therapists feel, knows what he is getting into. If she thins out, that could mean he's getting less than he bargained for. "The more weight that is lost," says Stuart, "the higher the probability of a shift in power."

So while a wife's weight loss makes a good marriage better, "it doesn't help a marriage that is dependent on the woman being insecure -- and can make it worse," says Jacobson.

"Weight changes are seldom just matters of weight. The woman who's lost 40 or 50 pounds is usually completely different. And if the marriage can't adjust to having a secure, self-confident person, it's probably better off being dissolved."

Stuart is a little more optimistic. "A weight loss," he believes, "provides an opportunity for the couple to develop a more satisfying and equitable relationship."

From age 19 to 26, Barbara Jacobson weighed one-third more than she does now -- four dress sizes larger. She was, she says, "one of those women who created a weight problem by buying into the whole diet thing. Then the deprivation created the desire" to eat, and the circle was complete.

"What finally happened is, I got tired of worrying about it," she says. "I decided I wanted to be healthy, and started exercising. I put all that attention on diets and spent it on making my life better."

Don't confuse this with "stop thinking about the problem and it will go away." It's not a case of forgetting about food and dieting -- just of redirecting energy.

One of the problems with the self-help genre (a field Weight, Sex and Marriage only loosely belongs to) is that it can make things like redirecting energy seem simple. A successful diet is hard enough -- as is proven by the millions of weight-loss books being sold each year. But changing the emotional basis for being overweight is obviously more difficult still.

"My husband is much younger than me," wrote a 56-year-old woman, when she answered the questionnaire. "He drinks a lot and hits me when I say the wrong words. I work hard for him and buy him expensive things, but he still cheats on me. Since I lost my job because of sickness, we don't have money to buy diet foods and I eat a lot of junk food, especially when he's out all night. Can you give me some pointers?"

"Dieting isn't going to do it for her," says Stuart. "Real change is needed. That's very different from the 40-year-old woman whose kids are grown and eats out of boredom.

"It's a whole lot easier for the second woman than the first. The amount of energy required equals the severity of the problem. Most are not terribly difficult. Some defy the imagination."